Don't just strengthen your muscles. Strengthen your lungs with PowerLung breathing devices. PowerLung is a great lung training device, allowing you to adjust resistance with every inhale and exhale. Browse the HeartRateMonitorsUSA.com catalog today, and find items such as the PowerLung BREATHEAIR (fitness/active lifestyle), PowerLung TRAINER (training and exercise/advanced performers), Powerlung PLW-16 Hypoallergenic Washer, and Many More.